PROJECT SUMMARY: Tobacco product labeling is a critical public health policy, and most countries around the world require health warning labels (HWLs) on cigarette pack exteriors. One labeling option is cigarette package inserts ? small printed leaflets inside of cigarette packs. For over a century, cigarette manufacturers have used inserts to reach smokers with promotional messages every time they open a new pack. However, inserts remain underused for public health communication. Canada is the only country in the world that has both HWLs and inserts, for which our recent research finds very promising results on their effectiveness for helping smokers quit. The US Food and Drug Administration currently is developing new labels for cigarettes in the US, and research is urgently needed to support its decision making. Our proposed study is based on the importance of ?efficacy? messages about the benefits of behavior change and that build confidence to change behavior, which is the type of message used on Canadian inserts. Efficacy messages on inserts may be most effective when accompanied by large pictorial HWLs that show harms from smoking. We aim to evaluate whether inserts with efficacy messages promote smoking cessation: AIM 1: We will evaluate the impact of inserts with efficacy messages using an experiment among adult smokers in the US. In Study 1, 320 smokers will be put into one of four labeling groups: 1. no inserts or pictorial HWLs; 2. inserts only; 3. pictorial HWLs only; 4. inserts & pictorial HWLs. Smokers will be given a 14- day supply of their preferred cigarette brand with packs labeled according to their group. Participants will answer a brief survey at the end of each day and four other times each day. We will study whether smokers in each group experience different psychological responses or behaviors associated with smoking cessation. AIM 2: We will evaluate the impact of an `inserts' labeling policy in Canada by following two groups of adult smokers who will be surveyed before and after Canada puts new inserts and HWLs on packs in 2020. Study 2a participants will answer surveys for 14 days (as in Study 1) both before and after the new policy is in place. In Study 2b we will survey 1500 smokers every 4 months over 2 years, covering the period before (3 surveys) and after (4 surveys) the new policy. The timing and questions for Studies 2a and 2b will allow us to compare their results, which will help us reach stronger conclusions about whether labels promote smoking cessation. The proposed study will provide the strongest research on package inserts to date. The strengths of the experiment in Study 1 are complemented by the evaluation of insert effects in more natural contexts for Studies 2a and 2b. Comparison of results across all three studies will help determine how inserts and HWLs work, including their effects on smoking cessation. The results will be useful for policy making both in the US and internationally. We will also improve understanding of product labeling, whose low cost and ability to repeatedly communicate with many people holds great potential for promoting healthy consumer behaviors.